公共汽车

公共汽车 (gōnggòng qìchē) is the formal Chinese word for 'public bus' — the four-character compound literally reads 'public-shared gas-vehicle.' It's the term taught in HSK textbooks and printed on official signage, but in everyday spoken Mandarin on the mainland, people almost always shorten it to 公交车 (gōngjiāochē), or just 公交 in compounds like 公交卡 (bus card) and 公交站 (bus stop). Taiwan tends to say 公车 (gōngchē). The word refers specifically to a city bus on a fixed route — not a long-distance coach (长途汽车), shuttle (班车), or school bus (校车). When you board, you tap a 公交卡 or scan a phone QR code; fares are usually flat. Saying 公共汽车 in casual conversation isn't wrong, just a tiny tell that you learned Chinese from a textbook.

Note: Textbook word. In daily conversation most mainland speakers shorten it to 公交车 (gōngjiāochē) or just 公交; in Taiwan, people say 公车 (gōngchē).

Memory hook: Break it apart: 公共 (public-shared) + 汽车 (gas-vehicle = car). A car that everyone shares = a bus.